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# Copyright (C) 2016 Nippon Telegraph and Telephone Corporation.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import struct
import logging
from . import packet_base
from os_ken.lib import type_desc
LOG = logging.getLogger(__name__)
UDP_DST_PORT = 4789
UDP_DST_PORT_OLD = 8472 # for backward compatibility like Linux
class vxlan(packet_base.PacketBase):
"""VXLAN (RFC 7348) header encoder/decoder class.
An instance has the following attributes at least.
Most of them are same to the on-wire counterparts but in host byte order.
__init__ takes the corresponding args in this order.
============== ====================
Attribute Description
============== ====================
vni VXLAN Network Identifier
============== ====================
"""
# Note: Python has no format character for 24 bits field.
# we use uint32 format character instead and bit-shift at serializing.
_PACK_STR = '!II'
_MIN_LEN = struct.calcsize(_PACK_STR)
# VXLAN Header:
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# |R|R|R|R|I|R|R|R| Reserved |
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# | VXLAN Network Identifier (VNI) | Reserved |
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
def __init__(self, vni):
super(vxlan, self).__init__()
self.vni = vni
@classmethod
def parser(cls, buf):
(flags_reserved, vni_rserved) = struct.unpack_from(cls._PACK_STR, buf)
# Check VXLAN flags is valid
assert (1 << 3) == (flags_reserved >> 24)
# Note: To avoid cyclic import, import ethernet module here
from os_ken.lib.packet import ethernet
return cls(vni_rserved >> 8), ethernet.ethernet, buf[cls._MIN_LEN:]
def serialize(self, payload, prev):
return struct.pack(self._PACK_STR,
1 << (3 + 24), self.vni << 8)
def vni_from_bin(buf):
"""
Converts binary representation VNI to integer.
:param buf: binary representation of VNI.
:return: VNI integer.
"""
return type_desc.Int3.to_user(bytes(buf))
def vni_to_bin(vni):
"""
Converts integer VNI to binary representation.
:param vni: integer of VNI
:return: binary representation of VNI.
"""
return type_desc.Int3.from_user(vni)
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